Shifting the Reactivity of Bis-propargyl Ethers from Garratt-Braverman Cyclization Mode to 1,5-H Shift Pathway To Yield 3,4-Disubstituted Furans: A Combined Experimental and Computational Study.
J Org Chem
; 81(2): 450-7, 2016 Jan 15.
Article
en En
| MEDLINE
| ID: mdl-26675334
ABSTRACT
Aryl or vinyl substituted bis-propargyl ethers upon base treatment generally form phthalans via the Garratt-Braverman (GB) cyclization pathway. In a major departure from this usual route, several aryl/vinyl bis-propargyl ethers with one of the acetylenic arms ending up with 2-tetrahydropyranyloxy methyl or ethoxy methyl have been shown to follow the alternative intramolecular 1,5-H shift pathway upon base treatment. The reaction has led to the formation of synthetically as well as biologically important 3,4-disubstituted furan derivatives in good yields. The initially formed E isomer in solution (CDCl3) slowly isomerizes to the Z isomer, indicating greater stability of the latter. The factors affecting the interplay between the 1,5-H shift and GB rearrangement have also been evaluated, and the results are supported by DFT-based computational study.
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01-internacional
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MEDLINE
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En
Revista:
J Org Chem
Año:
2016
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Article
País de afiliación:
India